✨ History items as class instances

[aswetlow]

Proposed Changes

Deserializes history items (request, response, input) as class instances. Feature Request: #1415

Example:
if (this.$history.prev?.request instanceof AlexaRequest) will work. this.$history.prev?.request.isNewSession() as well.

Types of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project
• My change requires a change to the documentation
• I have updated the documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed